Many situations require a mechanism to immobilize a door in the closed position where locks have not heretofore been installed on the door or where keys to previously installed locks are not sufficiently controlled to prevent unauthorized entry. For example, construction sites, prior to completion, may use completed rooms with doors for the temporary storage of building materials and it is desirable that access be limited to authorized personnel.
Similarly, office buildings, hotels and hospitals may wish to secure, temporarily, otherwise unoccupied rooms which may not be provided with locks. Further, for those rooms with locks, it may be desirable to secure such rooms temporarily against use by persons who would normally have keys and therefore unrestricted access. Persons sharing living space such as multiple bedroom houses or apartments may wish to control access to rooms or closets without installing permanent locking devices. Condominium owners who permit rental of their dwelling may wish to keep personal property in room or closets without affording access to the renters and without wishing to install disfiguring locking arrangements.
Landlords may wish a simple device to bar entry to delinquent tenants or to protect property pending a change of the lock or in the event of damage to the lock as the result of an unauthorized forcible entry. Other instances will come to mind of situations where it would be desirable to have an easily demountable device that can be attached to a door and which can be quickly secured and released, using a padlock or a quick release pin, from either side, no matter which way the door opens.
Prior art devices have been proposed and generally fall into three categories: 1) Devices which are installed on an accessible side of the door and which engage the floor or a wall to resist movement of the door; 2) devices which are installed on the outside of an inwardly opening door and which provide a bar against the frame to hinder door opening; and 3) devices which are installed on a door frame or stop, but which can be secured from either side.
Patents illustrating devices of the first type include the patents to Tochihara, U.S. Pat. No. 4,198,088; Wilson, U.S. Pat. No. 4,560,192; Hudec, et al, U.S. Pat. No. 4,653,140; and Bell, U.S. Pat. No. 4,657,293. Patents teaching devices of the second type include the patents to Hudon, U.S. Pat. No. 3,181,319; Hagopian, U.S. Pat. No. 3,997,206; Sessions, Jr., U.S. Pat. No. 4,330,146; Vidas, U.S. Pat. No. 4,585,259; and Tobey, U.S. Pat. No. 4,653,785.
The patent to Johns, U.S. Pat. No. 4,405,165, illustrates the third type of device and includes a planar member for engaging one of the planar surfaces of the door and a tongue member extending from the planar member and adapted to protrude through the space between the door and the jamb when the door is closed. A collar plate fits over the tongue member and engages both the other planar surface of the door and the door stop portion of the frame. The planar member includes a sliding plate which can be brought into engagement with the door stop on the door frame. Means are provided for locking both the collar plate and the sliding plate so that the door can be secured from either side.
While the Johns device appears to be universal in its application, it has shortcomings. For one thing, a door stop can frequently be a thin strip of wood that is fastened to a door frame with small finishing nails and may not withstand any forceful attempt to open the door.
For example, to secure an inwardly opening door from the outside, which is, by far, the most common situation, one must mount the door jamb engaging member to straddlingly grip the door stop portion of the jamb. This is accomplished by positioning the end edge of the flat plate so that it overlays the side edge of the door stop shoulder with a projection that is provided on the flat plate. The collar ring, previously adjusted and locked with a set screw so that the distance between it and the flat plate is just slightly greater than the width of the door stop shoulder.
The set screw is then tightened against the shoulder, fixing the flat plate in place. The door engaging member is then slid into place and the tabs are aligned so that a lock or pin can be placed in aligned apertures. The door is then closed with the tongue protruding from the space between the door edge and the jamb. The collar plate is then slid onto the tongue and a lock is passed through aligned apertures in the tongue and plate. It is clear that if the thickness of the door is greater than the length of the tongue, the collar plate cannot be locked in place.
To open the door from the inside, the lock or pin is removed from the aligned tabs and the set screw against the door stop must be released. In an emergency, apparatus to release the set screws may not be readily available.
To lock an outwardly opening door from the inside, door engaging member is placed on the door and the collar plate is fastened to the tongue with a pin, bolt or lock. The door is then closed and the door jamb engaging member is slid into engagement with the door engaging member. The collar ring is then secured to the door stop with the set screw and a bolt or lock is placed through the aligned apertures.
As can be seen, the door jamb engaging portion requires some tool to engage the set screws which makes for a semipermanent installation on the door frame. Further, until the set screws are released from the door stop, the device cannot be easily deactivated from the "inside" in an emergency. In addition, the device requires separable parts that must be properly fitted and secured, not only to the door frame but to each other. The door jamb engaging member can also be a hazard because it will protrude into the door opening at a height that may strike passers by.
What is needed and what is provided by the present invention is a demountable door securing device that is unitary, can be released from both sides and which can be frictionally held at a convenient height. It would also be desirable for the device to be universal so that it can be installed on any door, no matter which side it is hinged.